Air cannons and other aeration equipment are often employed in association with material handling vessels in order to supply a discharge of compressed air to the vessel, so as to dislodge buildups and enhance the flow of material within the vessels. An air cannon stores a large volume of air or other gas under pressure in a pressure tank and then quickly releases the air into the material handling vessel, such that the blast of air causes any obstructing material therein to dislodge, thereby enabling the material to flow freely. Industrial applications where air cannons are commonly employed include coal-fired electric generating facilities; coal, metallic, and non-metallic mineral mines; steel mills and foundries; pulp and paper mills; grain, food, and chemical processing operations; aggregate, cement, and concrete producers; and bulk transportation facilities.
Generally, an air cannon's outlet valve is connected, via intermediate extension piping and associated flanges, to a discharge nozzle. The discharge nozzle has an inlet port accessible from the outside of the material handling vessel, and an outlet port positioned inside of the vessel, to distribute the gas released from the air cannon into the vessel's interior.
Depending upon the material handling application, air cannon nozzles can be subject to extreme environmental conditions. For example, one application of air cannons is in the manufacture of cement, where air cannons are employed, for example, in pre-heater towers, to maintain the flow of material through a series of vertical cyclone chambers, as the raw material passes on its way to a kiln and subsequent clinker cooler. As many as one hundred or more individual air cannons, and associated nozzles, may be employed in conjunction with a single pre-heater tower. Inside the cyclone chambers of the pre-heater tower, air cannon nozzles may be exposed to temperatures in excess of 2,500 degrees Fahrenheit for sustained periods of time. Moreover, at the same time, these nozzles are also in contact with caustic chemicals and materials. As a result, air cannon nozzles in such applications become worn over time, and must be periodically replaced. In addition to pre-heater towers, air cannon nozzles are commonly used in other high temperature environments, such as the clinker coolers employed in cement manufacture, and the lime kilns employed in the manufacture of calcium oxide, commonly known as quicklime.
With prior art air cannon nozzles, periodic replacement of the nozzles can be a significantly time consuming and costly undertaking, particularly when, as mentioned above, a single pre-heater tower at a cement plant may have in excess of one hundred nozzles in need of replacement, as may occur during a scheduled annual maintenance shutdown. In such environments, removal of a single prior art nozzle requires: 1) the separation of the air line from the air cannon; 2) the separation of the air cannon itself, including the exhaust valve and associated pressure tank, from an extension pipe coupling the exhaust valve to the nozzle; 3) the separation of the extension pipe from the nozzle; 4) the removal of worn refractory material from a region of the interior of the vessel surrounding the nozzle; and 5) the separation of the nozzle from the wall of the vessel. Subsequent attachment of a replacement prior art nozzle then requires: 1) one person to hold the nozzle from inside of the vessel, while another tacks the nozzle into place (since mounting orientation of the nozzle may be critical, several attempts at positioning and repositioning of the nozzle may be required to correctly position the nozzle; 2) welding the nozzle to the vessel; 3) welding the extension pipe to the nozzle; 4) attaching the air cannon to the extension pipe; and 5) reattaching the air line to the air cannon.
Accordingly, it is an object of the present invention to provide an air cannon nozzle which is easier and hence less costly to replace, once installed in association with an air cannon and a material handling vessel.
It is another object of the present invention of the present invention to provide an air cannon nozzle which is suitable for use in both ambient and high temperature environments.
It is yet another object of the present invention to provide an air cannon nozzle which is capable of withstanding high temperature environments for prolonged periods of time.
These and other objects and features of the present invention will become apparent in view of the present specification, drawings and claims.